Linda, you do not have Alzheimer's. I thought I did too when the fog hit. It can be scary but don't worry about it. It's not constant.
Many with fibro have arthritis and some THINK they have arthritis since fibro affects the muscles, tendons and ligaments. I've had joints that I swore were arthritic. They were extremely sore, I'd have swelling, and even warmth. It would last for months and then go away. Arthritis doesn't do that, as far as I know. Arthritis damages the joints so it doesn't go away but fibro doesn't hurt the joints at all. It's muscle pain that is being felt.
Also, many with fibro have IBS. I keep saying many because not all have arthritis or IBS. So, they really don't go hand in hand. At least that's my humble opinion.
I started taking malic acid/magnesium supplements last December and that has helped me a lot. They help with pain and fatigue and you could sleep better too. The magnesium helps with that. My cousin started sleeping so much better once she started this. Now, it doesn't work for everyone, but it is worth a shot. They aren't expensive, either, at least where I get mine. I wrote a thread all about it and I'll bump it up for you.
Try, also, to put yourself on a sleep schedule. That does help with sleeping. Also, avoid caffeine. (Don't forget there is caffeine in chocolate.) That keeps many awake! I usually get a little sleepy in the afternoon and I do have a cup of hot tea. There is not nearly as much caffeine in the tea than in coffee. It's just enough to give me a boost but I still can sleep at night. Also, I would stay away from candy and a lot of carbs during the day. You know that they raise your blood sugar and that can make you sleepy, too.
But, I still wake up many times a night. It does go with the territory but I'm not exhausted all day long. Once I get up and moving, I do just fine. Be sure to do walking and gentle exercises.
Check out the Fibro 101 thread. It's the second thread from the top of the forum. There are links to stretching exercises and other good stuff. I'm sure, being a nurse, you get plenty of walking in, though.
I do hope some of this helps you. Let us know!
Sherrine